Beginning in America’s Progressive Era, scientific and regulatory efforts to use animal feed stuffs to control the production of human food emerged with the development of new technologies and professional organizations. Across the 20th century, the Food and Drug Administration (FDA), American Society of Animal Nutrition (ASAN), and American Feed Manufacturers Association (AFMA) worked together to persuade feed mills and farmers to change their practices for the sake of food safety, economic efficiency, and the health of both humans and animals. Tracing this development of America’s animal feed industry and the shifting conceptualizations of feed stuffs through the 20th century, this project explores how the relationships humans build with their domesticated animals can not only affect federal policy and economic markets, but also bodies and landscapes.